Modern Solar thermal energy can be a economical way of generating clean electrical energy on a large scale.
Solar thermal energy is the use of solar heat energy striking mirrors which focus the heat on to pipes carrying water.
Steam is created which can be used directly or feed into turbines to generate electricity.
The largest system to date is 9 solar thermal plants in California's Mojave Desert that generate at total of 354 MW of electricity.

With the world concerned about climate change and sustainable energy, solar thermal energy is once again becoming popular.
50 MW solar thermal plants with thermal storage using molten salt have been set up in Spain under the name Andasol 1 2 3.
Thermal storage allows for electricity generation at night or when overcast.
Ausra has completed a 25 MW steam to 5 MW electricity plant in 2008 for $15 M US.
An Ausra proposed 177 MW solar thermal plant would cost $500 M US and cover 1 square mile.
Other solar thermal plants are expected in the USA, Spain and Australia.